1. Technical Field
This application generally relates to a computer system, and more particularly to the management of local and remote group data within the computer system.
2. Description of Related Art
Computer systems may include different resources used by one or more host processors. Resources and host processors in a computer system may be interconnected by one or more communication connections. These resources may include, for example, data storage devices such as the Symmetrix™ family of data storage systems manufactured by EMC Corporation. These data storage systems may be coupled to one or more host processors and provide storage services to each host processor. An example data storage system may include one or more data storage devices, such as those of the Symmetrix™ family, that are connected together and may be used to provide common data storage for one or more host processors in a computer system.
A host processor may perform a variety of data processing tasks and operations using the data storage system. For example, a host processor may perform basic system I/O operations in connection with data requests, such as data read and write operations.
Host processor systems may store and retrieve data using a storage device containing a plurality of host interface units, disk drives, and disk interface units. Such storage devices are provided, for example, by EMC Corporation of Hopkinton, Mass. and disclosed in U.S. Pat. No. 5,206,939 to Yanai et al., U.S. Pat. No. 5,778,394 to Galtzur et al., U.S. Pat. No. 5,845,147 to Vishlitzky et al., and U.S. Pat. No. 5,857,208 to Ofek. The host systems access the storage device through a plurality of channels provided therewith. Host systems provide data and access control information through the channels to the storage device and storage device provides data to the host systems also through the channels. The host systems do not address the disk drives of the storage device directly, but rather, access what appears to the host systems as a plurality of logical disk units. The logical disk units may or may not correspond to the actual disk drives. Allowing multiple host systems to access the single storage device unit allows the host systems to share data stored therein.
A data storage system, such as the Symmetrix data storage system, may include multiple devices. A group of devices may be defined and referenced by a group name. Devices included in a group may all be within the same data storage system, as well as located on different data storage systems. Group names may be associated with multiple devices for any one of a variety of different uses. Multiple hosts may reference the same group name to refer to the same set of one or more devices associated with the group name. A first device included in a group may be a local device included in a first data storage system connected to a host. The first device may have an associated remote device included in a remote data storage system. The remote device may include, for example, a backup copy of data from the first device for use in the event of problems with data on the first device. It may be desirable to provide a technique for creating and maintaining a remote mirror of the group on the remote data storage system. It may be desirable that this technique also provide for synchronizing any modifications to a group at both the local and remote data storage systems and host using the group.